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Light and Vision

LIGHT

What is Light?

What do we want to know about it?

Light has different significance for different people, depending on their perspective.

People relate to light and how they intend to use it.

LIGHT - Technician

• For the Technician or Scientist, light is the visible spectrum – a part of the spectrum of electromagnetic energy that excites our neurological visual system that enables us to see.

• Light can be measured, calculated, and controlled – light is radiant energy.

LIGHT - Writer

Light = noun, adjective

- something that makes things visible or affords illumination: All colors depend on light.

Light = adjective

- having light or illumination; bright; well-lighted: the lightest room in the entire house.

- pale, whitish, or not deep or dark in color: a light blue. - of coffee or tea) containing enough milk or cream to produce

a light color.

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Light and Vision

LIGHT - Poetic

For the poet, it might be a metaphor …

• QUOTATION: Not every light is a true light;To the wise the light of truth is light itself.

Tiruvalluvar (c. 5th century A.D.), Tamil sage, poet.

or a connotation of mood …

• QUOTATION: A sudden light transfigures a trivial thing, a weather-vane, a wind-mill, a winnowing flail, the dust in the barn door; a moment,—and the thing has vanished, because it was pure effect; but it leaves a relish behind it, a longing that the accident may happen again.

Walter Pater (1839–1894), British writer, educator.

LIGHT - Painter

• Edward HopperAm. 1882 - 1967

• Morning Sun 1952His paintings embody in art a particular American 20th-century sensibility that is characterized by isolation, melancholy, and loneliness.The stark play of light and shadow convey an atmosphere of all-embracing loneliness and almost eerie solitude - the mood was the real subject of the work.

To the Artist, light is a vehicle of expression.

LIGHT - Painter

• Johannes VermeerDutch (1632 – 1675)

• Young Woman with a Water Pitcher c. 1662

• Soft light subtly portrays the tranquility of domestic life. Conveys a sense of well –being.

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Light and Vision

LIGHT - Painter

Giacomo Balla

LIGHT - Photographer

LIGHT - Light Artist

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Light and Vision

LIGHT - Light Artist

LIGHT - Light Artist

LIGHT - Industrial Designer

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Light and Vision

LIGHT - Fixture Designer

• The Industrial or Product Designer looks at light as a physical object, designed to satisfy a lighting need in a stylistically interesting

package.

LIGHT - Fixture Designer

sight line

sight line

LIGHT – Environmental Designer

• creating an atmosphere

• creating a sense of space, both physically and experientially/psychologically

• describing materials and surfaces

• meeting the needs of use of the space

The Architect and Interior Designer are interested in the environmental impact of light.

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Light and Vision

LIGHT – Lighting Designer

LIGHT – Lighting Designer

LIGHT – Lighting Designer

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Light and Vision

LIGHT – Lighting Designer

LIGHT – Lighting Designer

LIGHT – Lighting Designer

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Light and Vision

Designing with Light

While our primary point of view as Interior Designers is environmental, all other considerations:

• scientific, • poetic, • artistic,• industrial design,

impact and inform our decisions as we develop a Lighting Design

Designing with Light

The majority of the information that we receive about the world around us comes through our eyes.

Light is not only an essential prerequisite, it is the medium by which we are able to see.

Through its intensity, the way it is distributed and through its properties, light creates specific conditions which can influence our perception. Lighting design is, in fact, the planning of our visual environment.

Good lighting design aims to create perceptual conditions which allow us to work effectively and orient ourselves safely while promoting a feeling of well-being in a particular environment.

Designing with Light: Perception

• An awareness of objects and other data through the medium of the senses: – visual perception = seeing

• Insight or intuition as an abstract quality: – visual perception = projecting meaning on what we see

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Light and Vision

Designing with Light

• Light plays a central role in the design of a visual environment. • The architecture, people and objects are all made visible by the

lighting. • Light influences our well-being, the aesthetic effect and the mood of

a room or area.

• It is light that first enables “what you see”.

Vision

Light Sources

Generators –Transmitters

Secondary Light Sources

Modifiers and Re-transmitters

Eyes

Receivers –Encoders

Brain

Decoder –Interpreter

Sun, Discharge lamps, fluorescent lamps.

Incandescent lamps, Open flames, etc.

Atmosphere, Air, Water, Planets, Lenses, Windows, Tress – All natural or

manufactured objects which modify light waves before they reach the eye.

Cornea, Iris, Lens, Rods & Cones, Optic Nerves

Analysis, Identification Association Perception

Visual System

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Light and Vision

Structure of the Eye

Cornea

Iris

Lens

Retina

Fovea

Light Entering the eye is projected upside down!

Eye’s Field of VisionCentral field of vision:

~2 degrees above and below the direct line of sight Visual acuity (ability to see detail) is best in this range

Peripheral area: Horizontal area to the sides of the central vision Vertical areas above and below the central field of vision

Brightness and motion best seen in peripheral vision

central field of vision

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Light and Vision

Processing of Visual Information

Color Perceptionthis visual process provides us details regarding the color of a surface or an object

the cones detect color…..a normal person is trichromatic…we see all colorsColor Deficiencies in the Visual System - color blindness

Photopic – Day Vision (Cones vision)

The cones of the eye are of three different types. These are the primary colors (additive) in light,

which are red, green, and blue.

Scotopic – Night Vision (Rods vision)

The rod is responsible for night and peripheral

vision.

Mesopic - Dim Light Vision (Rod and Cone vision)

This occurs when the light levels are low but there still is the ability to see color (between .01 and 1 cd/m2 adaptation luminance).

Day & Night Vision

Measuring VisionVisual Acuity (20/20 Vision)Snellen Eye Chart: the first number is refers to the distance from the chart, the second is what a normal person can read the chart….20/20 is normal…but, 20/60 says that person could read 20 feet what normal person can read at 60 feet

Contrast SensitivityContrast Detection

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Light and Vision

Effects of AgingYellowing of the lensOpacity of the lensLess Elastic LensAmount of light reaching the RetinaTime required for Visual ProcessVisual Acuity and Sensitivity decrease

Common Defects:

Myopia: can’t focus on far objects (Near-sighted)

Hyperopia: can’t focus on near objects (Farsightedness)

Astigmatism: distortion in the shape of the lens

Presbyopia: lens loses it elasticity….corrected with bifocals to read near

Functions Performed by the EyeYou can NOT control

AdaptationHow?1. The Pupil Size changes, 2. Photochemical - the cones and rods bleach3. Transient – over time

You can controlAccommodation How?1. The lens changes shape to focus

Eye MovementHow?1. The eye can move smoothly or jump using six muscles around the eye2. Binocular – using both eye…..Monocular – using one eye

Visibility and Visual Performance

ContrastSizeBackground LuminousViewing Time